The gathering comes just hours after Russian authorities granted temporary asylum to Edward Snowden, the former Defense contractor who leaked details about the programs to a handful of newspapers. Snowden is seeking to avoid extradition to the U.S. where he faces espionage charges.

The administration is making a push to assuage lawmaker concerns about the NSA. The agency's Director Gen. Keith Alexander will provide a classified briefing to House lawmakers on Thursday.

The Obama administration also declassified new documents Wednesday providing details on how the NSA collects records on phone calls within the United States.

President Obama responded to concerns over the top-secret surveillance programs during a closed-door meeting with Democratic senators Wednesday on Capitol Hill.

But that could be a tall order with some of the lawmakers, including Udall and Wyden, who have long warned that the government was overreaching with its surveillance efforts. In an interview with CNN on Wednesday, Wyden accused leaders in the intelligence community of having "kept Congress in the dark."

"The Congress have been given inaccurate statements and, in effect, been actively misled," Wyden said.

Asked about the presidential meeting by The Hill, Wyden said he wouldn't comment publicly until the conversation took place.

"I'll be going to that meeting. I'll have something to say after that," he said.

Further details about the NSA's programs continue to emerge. Earlier Wednesday, The Guardian reported that the agency was running a program named XKeyscore that allows intelligence analysts to search databases containing nearly every type of action made by Internet users, including email, online chats and browser history.

White House press secretary Jay Carney said Wednesday that he did not know whether members of Congress had been informed about the XKeyscore program, but also declared "some of the claims made in that article are false."

"As we've explained and the intelligence community has explained, allegations of widespread, unchecked analyst access to NSA collection data are false," Carney said during the daily White House press briefing. "Access to all of NSA's analytic tools is limited to only personnel who require access for their assigned tasks, and there are multiple technical, manual and supervisory checks within the system to prevent from those who don't have access from achieving that access."